Self-ligating orthodontic bracket

Abstract

An orthodontic bracket for coupling an archwire with a tooth includes a bracket body, a hinge pin, and a latch. The bracket body includes a first surface configured to be mounted to the tooth and an archwire slot in a second surface. The hinge pin includes a first shaft portion coupled with the bracket body. The latch is coupled to the bracket body by a second shaft portion of the hinge pin. The latch is movable between an opened position and a closed position. A cross-sectional profile of the first shaft portion and/or the second shaft portion of the hinge pin is configured to elastically deform to impart a spring bias to the latch that opposes movement of the latch relative to the bracket body.

What is claimed is: 
     
       1. An orthodontic bracket for coupling an archwire with a tooth, the orthodontic bracket comprising:
 a bracket body configured to be mounted to the tooth and including an archwire slot having opposing first and second slot sides and a third slot side extending between the opposing first and second slot sides; 
 a hinge pin including a first shaft portion operatively coupled with the bracket body and a second shaft portion; and 
 a latch operatively coupled to the bracket body by the second shaft portion of the hinge pin for rotational movement about an axis of rotation defined by the hinge pin, the latch being movable between an opened position in which the archwire is insertable into the archwire slot and a closed position in which the latch retains the archwire in the archwire slot, 
 wherein a cross-sectional profile of the first shaft portion and/or a cross-sectional profile of the second shaft portion of the hinge pin is configured to elastically deform to impart a spring bias to the latch that biases the latch in a direction intersecting a plane defining the third slot side, the cross-sectional profiles of each of the first shaft portion and the second shaft portion being taken perpendicular to the longitudinal axis of the respective shaft portion. 
 
     
     
       2. The orthodontic bracket of  claim 1  wherein one of the first shaft portion and the second shaft portion of the hinge pin is configured to elastically deform from a first cross-sectional profile when the latch is in the closed position to a second cross-sectional profile when the latch is moved from the closed position, the spring bias opposing movement of the latch from the closed position, and the first cross-sectional profile and the second cross-sectional profile being different. 
     
     
       3. The orthodontic bracket of  claim 2  wherein one of the first shaft portion and the second shaft portion of the hinge pin is configured to elastically deform from the second cross-sectional profile to a third cross-sectional profile when the latch is rotated toward the opened position. 
     
     
       4. The orthodontic bracket of  claim 1  wherein the hinge pin is a hollow cylinder. 
     
     
       5. The orthodontic bracket of  claim 1  wherein the bracket body includes a bore for receiving the first shaft portion and the latch includes an aperture for receiving the second shaft portion and at least one of the aperture and the bore has a non-symmetric cross-sectional profile, the non-symmetric cross-sectional profile being in the same plane as the corresponding shaft cross-sectional profile and with the non-symmetry being determined across a plane that includes the axis of rotation. 
     
     
       6. The orthodontic bracket of  claim 1  wherein the bracket body includes a bore for receiving the first shaft portion and the latch includes an aperture for receiving the second shaft portion, the bore including a bore cross-sectional profile and the aperture including an aperture cross-sectional profile, each of the cross-sectional profiles being in the same plane as the corresponding shaft cross-sectional profile, one of the bore cross-sectional profile and the aperture cross-sectional profile being substantially non-congruent relative to the corresponding cross-sectional profile of the first shaft portion or second shaft portion, the hinge pin being configured to move relative to the bore or the aperture and elastically deform toward at least a portion of the substantially non-congruent cross-sectional profile. 
     
     
       7. The orthodontic bracket of  claim 6  wherein the aperture cross-sectional profile is substantially non-congruent relative to the cross-sectional profile of the second shaft portion and includes a central portion and a first narrowed end, the second shaft portion being located in the central portion when the latch is in the closed position and elastically deforms into the first narrowed end when the latch is moved from the closed position. 
     
     
       8. The orthodontic bracket of  claim 7  wherein the central portion of the aperture cross-sectional profile is sized to elastically deform the hinge pin in the closed position. 
     
     
       9. The orthodontic bracket of  claim 6  wherein the substantially non-congruent cross-sectional profile includes a first narrowed end that is contiguous with a central portion and wherein one of the first shaft portion and the second shaft portion is located in the central portion when the latch is in the closed position and elastically deforms into the first narrowed end when the latch is moved from the closed position. 
     
     
       10. The orthodontic bracket of  claim 9  wherein the substantially non-congruent cross-sectional profile includes a second narrowed end that is contiguous with the central portion and one of the first shaft portion and the second shaft portion elastically deforms into the second narrowed end when the latch is moved toward the opened position. 
     
     
       11. The orthodontic bracket of  claim 10  wherein the latch includes an outer periphery including a cam surface configured to contact the bracket body and move the latch in a non-collinear direction relative to the axis of rotation when the latch is rotated about the axis of rotation from the closed position to the opened position. 
     
     
       12. The orthodontic bracket of  claim 11  wherein the cam surface is configured to contact the bracket body to hold the latch in the opened position. 
     
     
       13. The orthodontic bracket of  claim 1  wherein the bracket body includes a shoulder engaged with the latch when the latch is in the closed position, so as to inhibit movement of the latch about the axis of rotation from the closed position toward the opened position, the spring bias of the hinge pin opposing movement of the latch away from the shoulder. 
     
     
       14. The orthodontic bracket of  claim 1  wherein the side of the latch that closes off the archwire slot when the latch is in the closed position is movable in a direction away from the axis of rotation when the latch is moved toward the opened position. 
     
     
       15. The orthodontic bracket of  claim 1  wherein the hinge pin is compressed when the latch is in the closed position. 
     
     
       16. The orthodontic bracket of  claim 1  wherein the bracket body includes a shaped projection for insertion into a corresponding receptacle formed on a pad that is configured to be secured to a tooth. 
     
     
       17. The orthodontic bracket of  claim 1  wherein elastic deformation includes a change in at least one dimension of the cross-sectional profile of one of the first shaft portion and the second shaft portion in a direction perpendicular to the longitudinal axis of the hinge pin. 
     
     
       18. The orthodontic bracket of  claim 17  wherein the bracket body includes a bore for receiving the first shaft portion and the latch includes an aperture for receiving the second shaft portion, wherein the change in the at least one dimension of the cross-sectional profile is to conform the at least one dimension to a dimension on the corresponding one of the bore or the aperture. 
     
     
       19. The orthodontic bracket of  claim 17  wherein the cross-sectional profile of the hinge pin is configured to elastically deform at the location of contact between the hinge pin and the latch or the hinge pin and the body. 
     
     
       20. An orthodontic bracket for coupling an archwire with a tooth, the orthodontic bracket comprising:
 a bracket body including an archwire slot having opposing first and second slot sides and a third slot side extending between the opposing first and second slot sides; 
 a pin; and 
 a latch including a pin aperture to receive the pin and being operatively coupled to the bracket body by the pin for rotational movement between an opened position and a closed position, the latch including a closure portion having a surface that opposes the third slot side when the latch is in the closed position, 
 wherein when the latch is in the closed position, the pin is elastically deformed so as to impart a spring bias to the latch to maintain the latch in the closed position. 
 
     
     
       21. The orthodontic bracket of  claim 20  wherein the latch is L-shaped. 
     
     
       22. The orthodontic bracket of  claim 20  wherein when the bracket body is mounted to the tooth, the archwire slot opens in the occlusal direction and the closure portion is biased in the gingival direction when the latch is in the closed position. 
     
     
       23. The orthodontic bracket of  claim 20  wherein to move the latch to the opened position from the closed position, the closure portion is moved in a direction away from the longitudinal axis of the pin. 
     
     
       24. The orthodontic bracket of  claim 20  wherein when the latch is in the opened position, the pin is in a non-stressed state. 
     
     
       25. An orthodontic bracket for coupling an archwire with a tooth, the orthodontic bracket comprising:
 a bracket body including an archwire slot having opposing first and second slot sides and a third slot side extending between the opposing first and second slot sides, the third slot side being configured to face in an occlusal direction when the bracket body is attached to the tooth; 
 a pin; and 
 a latch being operatively coupled to the bracket body by the pin for rotational movement between an opened position and a closed position, the latch having a closure portion facing the third slot side when the latch is in the closed position, the third slot side being between the closure portion and the pin, the pin being elastically deformed when the latch is moved from the closed position to the opened position. 
 
     
     
       26. The orthodontic bracket of  claim 25  wherein the bracket body includes a shoulder engagable with the latch when the latch is in the closed position so as to inhibit movement of the latch about the axis of rotation from the closed position toward the opened position, wherein the closure portion is moved away from the third slot side to clear the shoulder to move the latch toward the opened position. 
     
     
       27. The orthodontic bracket of  claim 25  wherein the bracket body further includes a side that is configured to be coupled to a surface of the tooth, the side being substantially perpendicular to the third slot side. 
     
     
       28. The orthodontic bracket of  claim 25  wherein the pin is elastically deformed so as to impart a spring bias to the latch to maintain the latch in the closed position. 
     
     
       29. The orthodontic bracket of  claim 28  wherein when the latch is in the opened position, the pin is in a non-stressed state. 
     
     
       30. The orthodontic bracket of  claim 25  wherein to move the latch to the opened position from the closed position, the closure portion is moved in a direction away from the longitudinal axis of the pin.